|Adelophryne michelin |
Lourenço-de-Moraes, Dias, Mira-Mendes, Oliveira, Barth, Ruas, Vences, Solé & Bastos, 2018
The number of species of frogs in the South American genus Adelophryne has increased in recent years, and it has become apparent that this group contains a substantial amount of undescribed diversity. Currently the genus contains nine described species and five candidate species. Here we describe the tenth species of the genus Adelophryne from the municipality of Igrapiúna, southern Bahia state, Brazil. The new species is characterized by its small body size, indistinct tympanum, and two phalanges in the finger IV. The species of the genus are distributed in three groups, Northern Amazonia Clade, Northern Atlantic Forest Clade and Southern Atlantic Forest Clade. The new species is phylogenetically related to species of the Northern Atlantic Forest Clade of Adelophryne and restricted to forested habitat, as typical for other Adelophryne. The species is restricted to the pristine forests in the type locality, and we consider its conservation status as Near Threatened. New morphological and molecular data of other Adelophryne species are presented, extending the distribution of Adelophryne sp. 2, Adelophryne sp. 4, Adelophryne mucronata and Adelophryne glandulata. However, a more comprehensive revision of the diversity and phylogenetic position of most Adelophryne species is needed, and the evolutionary relationships of A. meridionalis and A. pachydactyla remain unknown.
Adelophryne michelin sp. nov.
Adelophryne sp. (Mira-Mendes et al. )
Etymology: The name “michelin” honors the Reserva Ecológica Michelin that has been supporting our researches for more than 10 years in the municipality of Igrapiúna, Bahia. The name is used as an invariable noun in apposition to the generic name.
Common name: Michelin Flea Frog or rãzinha-pulga-da-Michelin (in Portuguese).
Diagnosis: The new species is included in the subfamily Phyzelaphryninae because of the molecular evidence and by the presence of apically pointed digits; its leaf litter habitat; its terminal digits either barely or not expanded, and the SVL not exceeding 23 mm in SVL. In addition to the results of molecular analysis, the generic assignment of Adelophryne michelin sp. nov. is based on the possession of a head narrower than body, cranial crests absent, small size, with subdigital pad and mucronate tip on the fingers and toes, toes III and IV with discs and mucronate tips, and terminal phalanges of toes and fingers T-shaped.
The new species can be distinguished from species in the genus Phyzelaphryne by the absence of subarticular tubercles on fingers, for presenting indistinct tympanum, and reduction of the phalanges in the Finger IV. Phyzelaphryne has subarticular tubercles, distinct tympanum and no reduction of the phalanges.
The new taxon is diagnosed by the following combination of character states: (1) snout–vent length smaller than 11.5 mm (males 7.6–9.1 mm, N = 7; females 10.0–11.4 mm, N = 12); (2) tympanum indistinct without visible membrane; (3) tympanic annulus absent; (4) dentigerous processes of vomers present; (5) fingers without terminal discs, with mucronate tips, terminal phalanges T-shaped; (6) toes with terminal discs or circumferential grooves and mucronate tips; (7) terminal phalanges of toes T-shaped and sharply reduced; (8) Finger I shorter than Finger II; (9) Finger IV with two phalanges; (10) Toe III longer than Toe V; (11) subarticular tubercles absent on the fingers and toes (subdigital pads present); (12) belly skin smooth; (13) dorsum skin smooth; (14) anal flap absent.
|Fig 4. Adult individuals of Adelophryne michelin sp. nov. in life (A) female paratype MBML 10498 and (B) paratype but not identified. Individual (A) showing an unusual bluish coloration and (B) showing common coloration.|
Geographic distribution: Adelophryne michelin sp. nov. is known only from the type locality, at the Reserva Ecológica Michelin (REM), municipality of Igrapiúna, Bahia—Brazil (Fig 6).
Natural history, ecology and status conservation: Adelophryne michelin sp. nov. occurs in the leaf litter of primary forest. Two large ovarian eggs (2.0 mm) were found in one female of Adelophryne michelin sp. nov. (ZUFG 10697). We dissected five specimens of Adelophryne michelin sp. nov. one specimens there was nothing (ZUFG 10696) and four specimens revealed ants in their stomachs (ZUFG 10695 and 10697, MZUESC 17506, MBML10498). Beetles were found in stomachs of A. glandulata and ants were also found in A. glandulata  in A. gutturosa  and in A. mucronata . We recorded a new population of A. mucronata and A. sp. 2 (sensu Fouquet et al. ), both species living sympatrically and syntopically with A. michelin sp. nov. in the REM.
Adelophryne michelin sp. nov has only been recorded at the type locality, in the Atlantic Forest biome of southeast Bahia, being restricted to well preserved forests. Based on the forest remnants size of landscape its area of occupancy is <500 km². As such, this new species can be included under criterion B2a of IUCN Red List . Because we do not have data on habitat decline  or population data, we felt unable to fit the species into a threat category given that at least two of three conditions of criterion "B" need to be fulfilled for including a species into a threat category. Thus, we suggest that Adelophryne michelin sp. nov. should be listed as Near Threatened (NT) under the criterion B2a.
Ricardo Lourenço-de-Moraes, Iuri R. Dias, Caio V. Mira-Mendes, Renan M. de Oliveira, Adriane Barth, Danilo S. Ruas, Miguel Vences, Mirco Solé and Rogério P. Bastos. 2018. Diversity of Miniaturized Frogs of the Genus Adelophryne (Anura: Eleutherodactylidae): A New Species from the Atlantic Forest of northeast Brazil. PLoS ONE. 13(9): e0201781. DOI: 10.1371/journal.pone.0201781